The actual solution to the conflict between Jacob, his Adversary, and the Others, as shown in the season finale of Season 5 is actually access to SPAM, a processed, salty pork product of the Hormel corporation.
The reasons:
1. The Island has a native population of boars, making pork a favored source of meat for the Others (native islanders)
2. The Island attracts travelers from distant lands, carrying preserved and usually heavily salted meat products. For instance, the Black Rock, a slave-ship, was likely carrying a large supply of salt-preserved meat.
3. Like other islands in the Pacific, the Lost Island is visited by the US military. Like other islands in the Pacific the US army brings weapons of destruction for a traditional society – modern weapons (a large hydrogen bomb) and most likely army rations of SPAM.
4. It is a well established fact that with US army visits and bases, Pacific island diets changed from being based on relatively healthy fish, fresh pork, and vegetables to those based on SPAM and imported carbohydrates (rice, for instance).
5. The islanders’ (Others) desire for and familiarity with SPAM is likely exacerbated by DHARMA project shipments, which could result in a Cargo cult.
6. Jacob, the possibly divine ruler of the Island knows of these facts. He sees his peoples (Others) desire for SPAM. He is clearly interested in a natural lifestyle – he weaves a tapestry of hand-made thread, he is seen eating a freshly caught and simply prepared fish, he wears homespun clothing. He believes that to keep the Others pure and on a way to progress he must keep the SPAM away from them.
7. Jacob likely hides the SPAM in his dwelling.
8. Jacob’s Adversary wants to prove that people are corrupt and corruptible. He is deeply interested in seeing the Others prove him right – access to high-sodium, high-fat, processed SPAM (a product of a corrupt civilization) will be ideal.
9. In the season finale of Season 5, taking the appearance of John Locke, the Adversary leads the Others to Jacob’s dwelling. His goals are not merely the murder of Jacob, but the distribution of SPAM to the Others.
10. The craving for SPAM is clearly demonstrated in the scenes of the Others marching to Jacob’s dwelling – a number of them are seen rubbing their bellies, likely in anticipation of SPAM.
11. The answer to the question “what lies in the shadow of the statue” likely refers to the location of the SPAM stash.
12. Jacob’s final words “They are coming” refer to the Others flooding uncontrollably to claim the SPAM.